Patent application title: CHARGE CONTROL AGENT AND TONER COMPRISING THE SAME

Abstract:

Discussed herein are a charge control agent and toner comprising said
charge control agent. Said toner of the invention is comprised of a
resin, a colorant, and the charge control agent, wherein, said charge
control agent is comprised of a specific type of metal complexes. In the
invention, the charge control agent has excellent charge control
properties and the characteristics of uniform crystalline size, high
charge speed, high thermo stability, low moisture absorption, and good
compatibility with resin. The toner of the invention has excellent
electrical characteristics and produces stable image of high quality
under a wide range of environmental conditions without dusting and
fogging.

Claims:

1. A charge control agent comprising:a specific type of metal complexes
represented by the following chemical formula (1) or chemical formula
(2):in formula (1), R1 represents an hydroxyl group or an hydrogen
atom; R2 and R3 independently represent a substituted or
unsubstituted alkyl group with 1-12 carbon atoms, an alkenyl with 2-12
carbon atoms, an alkoxy group with 1-12 carbon atoms, a substituted or
unsubstituted aryl group with 6-12 carbon atoms, a nitryl group, an
amidogen group, an halogen atom, or an hydrogen atom; R4 represents
an hydrogen atom, a potassium atom, or a sodium atom; M represents a
metal atom ranges from divalent to tetravalent, A is a cation, and m is
an integer from 1 to 6;in formula (2), R1 represents an hydroxyl
group or an hydrogen atom; R2 and R3 independently represent
substituted or unsubstituted alkyls with 1-12 carbon atoms, an alkenyl
with 2-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, a
substituted or unsubstituted aryl group with 6-12 carbon atoms, a nitryl
group, an amidogen group, an halogen atom, or an hydrogen atom; R4
represents an hydrogen atom, a potassium atom or a sodium atom; R5
and R6 independently represent a hydroxyl group, a water molecule,
or a halogen atom; M represents a metal atom ranges from divalent to
tetravalent, A is a cation, and m is an integer from 1 to 6.

2. A toner comprising a resin, a colorant, and the charge control agent of
claim 1.

[0003]The invention is related to a charge control agent and the toner
containing such charge control agent.

[0004]2. Description of the Related Art

[0005]Charge control agent, mainly constituted by metal complexes, have
been extensively used in various areas, i.e., in the toner used in
forming developer for developing an image in electrophotographic
technology, in which the charge control agent is used as a component
material of such toners (e.g., please refer to patent documents: Public
Notice 63-61347, Public Notice 2-16916, Public Notice 2002-53539, Public
Notice 2531957, Public Notice 7-97530, Public Notice 2005-121776).

[0006]The metal complexes normally used as the charge control agent in
toners include generally known azo-metal complexes and salicylate-metal
complexes.

[0007]One side, in an image-forming process by an image-forming apparatus
using electrophotographic technology, it is necessary to heat the toner
image recorded on a transfer material to fix the image. In recent years,
low-temperature image fixing has been used to save energy.

[0008]However, in the chemical structure of azo-metal complexes and
salicylate-metal complexes, the metal ion often tends to detach from the
structure. As a result, in the toners using an azo-metal complexes or a
salicylate-metal complexes as the charge control agent, the detached
metal ion may bridge with the resin structure, which is another
ingredient of the toners. This will cause the softening-point temperature
of the toners to increase. Thus, high-quality image in low-temperature
fixing cannot be obtained. In addition, the image quality will be greatly
affected by humidity variations in the fixing environment. These are
existing problems.

[0009]Thus, metal-free chemicals, such as calixarene compounds, are used
as a charge control agent for toners. Comparing with the toners using
metal-complexes as charge control agent, the charge characteristics of
the toners using metal-free chemicals as charge control agent are
inadequate, and the charges on the toner particles are not uniform. As a
result, dusting and fogging of the toner occurs because the toners
particles are not sufficiently charged.

SUMMARY OF THE INVENTION

[0010]Based on the above-mentioned facts and the advanced research
conducted by the inventors, it is found that the key problems of
traditional charge control agent are non-homogeneous crystal sizes, high
moisture absorption, poor dispersion in resin, and high probability that
the metal ion will detach from the chemical structure. In view of the
above-described problems, it is one objective of the invention to provide
a charge control agent with excellent charge control properties.

[0011]Another objective of the invention is to provide a toner that is
capable of obtaining high-quality, stable image under a wide range of
environmental conditions.

[0013][In formula (1), R1 represents a hydroxyl ion or a hydrogen
atom; R2 and R3 independently represent an alkyl group with
1-12 carbon atoms, an alkenyl group with 2-12 carbon atoms, an alkoxy
group with 1-12 carbon atoms, an aryl group with 6-12 carbon atoms, a
nitryl group, an amidogen group, a halogen atom, or a hydrogen atom;
R4 represents a hydrogen atom, a potassium atom, or a sodium atom; M
represents a metal atom that may range from divalent to tetravalent; A is
a cation; and m is an integer from 1 to 6.]

[0014][In formula (2), R1 represents a hydroxyl ion or a hydrogen
atom; R2 and R3 independently represent an alkyl group with
1-12 carbon atoms, an alkenyl group with 2-12 carbon atoms, an alkoxy
group with 1-12 carbon atoms, an aryl group with 6-12 carbon atoms, a
nitryl group, an amidogen group, a halogen atom, or a hydrogen atom;
R4 represents a hydrogen atom, a potassium atom, or a sodium atom;
R5 and R6 independently represent a hydroxide group, a water
molecule, or a halogen atom; M represents a metal atom that may range
from divalent to tetravalent; A is a cation; and m is an integer from 1
to 6.]

[0015]The toner of the invention is comprised of a resin, a colorant, and
the charge control agent, wherein, the charge control agent is comprised
of a metal complexes represented by the chemical formula (1) or chemical
formula (2).

[0016]In the invention, the catechin gallate metallic complexes that
constitutes the charge control agent has the characteristics of uniform
crystal size, high charge speed, high thermo stability, low moisture
absorption, and good compatibility with the resin.

[0017]Hereafter is a detailed description of the invention.

[0018]The charge control agent of the invention is constituted by the
chemical compounds shown in the above Chemical Formula (1) (hereafter
referred to as `specific catechin gallate metallic complexes (1)`) or the
above Chemical Formula (2) (hereafter referred to as `specific catechin
gallate metallic complexes (2)`).

[0020]In the chemical formula (1) representing the specific catechin
gallate metallic complexes (1), R1 is a hydrogen atom or hydroxyl
ion. If R1 is a hydrogen atom, specific catechin gallate metallic
complexes (1) represents the compound that has the original ligand in the
catechin gallate derivative; if R1 is a hydroxyl ion, specific
catechin gallate metallic complexes (1) represents the compound that has
the original ligand in the epigallocatechin gallate derivative.

[0021]In chemical formula (1), R2 and R3 independently represent
an alkyl group with 1-12 carbon atoms, an alkenyl group with 2-12 carbon
atoms, an alkoxy group with 1-12 carbon atoms, an aryl group with 6-12
carbon atoms, a nitryl group, an amidogen group, a halogen atom, or a
hydrogen atom; R2 and R3 can be the same or they can be
different groups.

[0022]The alkyl group represented by R2 and R3 can be, for
example, a methyl group, an ethyl group, a propyl group, a butyl group,
an octyl group, a 2-ethylhexyl group, a decyl group, or a dodecyl group.

[0023]An alkenyl group represented by R2 and R3 can be, for
example, a 2-propylene group, a 2-octylene group, a 2-decylene group, or
a 2-laurylene group.

[0024]An alkoxy group represented by R2 and R3 can be, for
example, a methoxy(CH3O--) group, an ethoxy(C2H5O--)
group, a propoxy (C3H7O--) group, a butoxy (C4H9O--)
group, a phenoxy (C6H13O--) group, an octoxy
(C8H17O--) group, a decyloxy (C10H21O--) group, or a
dodecy (Cl2H25O--) group.

[0025]An aryl group represented by R2 and R3 can be, for
example, a phenyl group, a 4-toluene group, a 4-tert-butylbenzene group,
a 2,6-dimethylbenzene group, or a 2,4,6-trimethylbenzene group.

[0026]An halogen atom group represented by R2 and R3 can be, for
example, a chlorine atom, a bromine atom, or an iodine atom.

[0027]In addition, in chemical formula (1), R4 can be a potassium
atom, a sodium atom, or a hydrogen atom.

[0028]In addition, in chemical formula (1), M can be a metal atom that
ranges from divalent to tetravalent.

[0031]The counterion represented by A can be, for example, a hydrogen atom
(H.sup.+), an ammonium ion (NH4.sup.+), a sodium ion (Na.sup.+), or
a potassium ion (K.sup.+).

[0032]Preferred embodiments of specific catechin gallate metal complexes
(1) include the following compounds.

[0033](1-1) In the compound of chemical formula (1), R1 is a hydroxyl
group, R2, R3, and R4 are hydrogen atoms, M is a zinc
atom, A is a sodium ion, and m is 1.

[0034](1-2) In the compound of chemical formula (1), R1, R2,
R3, and R4 are hydrogen atoms, M is a zinc atom, A is a sodium
ion, and m is 1.

[0035](1-3) In the compound of chemical formula (1), R1 is a hydroxyl
group, R2, R3, and R4 are hydrogen atoms, M is a chromium
atom, A is a ammonium ion, and m is 1.

[0036](1-4) In the compound of chemical formula (1), R1 is a hydroxyl
group, R2, R3, and R4 are hydrogen atoms, M is a iron
atom, A is a sodium ion, and m is 1.

[0037](1-5) In the compound of chemical formula (1), R1, R2,
R3, and R4 are hydrogen atoms, M is a chromium atom, A is a
ammonium ion, and m is 1.

[0038](1-6) In the compound of chemical formula (1), R1 is a hydroxyl
group, R2 and R3 are methyl groups, R4is a hydrogen atom,
M is a zinc atom, A is a sodium ion, and m is 1.

[0039](1-7) In the compound of chemical formula (1), R1 is a hydroxyl
group, R2 and R3 are octyl groups, R4is a hydrogen atom, M
is a zinc atom, A is a sodium ion, and m is 1.

[0040](1-8) In the compound of chemical formula (1), R1 is a hydroxyl
group, R2 and R3 are dodecyl groups, R4is a hydrogen atom,
M is a zinc atom, A is a sodium ion, and m is 1.

[0041](1-9) In the compound of chemical formula (1), R1 is a hydroxyl
group, R2, R3, and R4 are hydrogen atoms, M is a zinc
atom, A is a kalium ion, and m is 1.

[0042](1-10) In the compound of chemical formula (1), R1 is a
hydroxyl group, R2, R3, and R4 are hydrogen atoms, M is a
zirconium atom, A is a sodium ion, and m is 1.

[0043](1-11) In the compound of chemical formula (1), R1 is a
hydroxyl group, R2, R3, and R4 are hydrogen atoms, M is an
aluminium atom, A is a sodium ion, and m is 1.

[0044](1-12) In the compound of chemical formula (1), R1 is a
hydroxyl group, R2 is a phenyl group, R3 and R4 are
hydrogen atoms, M is a zinc atom, A is a sodium ion, and m is 1.

[0045](1-13) In the compound of chemical formula (1), R1 is a
hydroxyl group, R2 and R3 are chlorine atoms, R4 is a
hydrogen atom, M is a zinc atom, A is a sodium ion, and m is 1.

[0046](1-14) In the compound of chemical formula (1), R1 is a
hydroxyl group, R2 and R3 are methyl groups, R4is a
hydrogen atom, M is an iron atom, A is a sodium ion, and m is 1.

[0047](1-15) In the compound of chemical formula (1), R1 is a
hydroxyl group, R2 and R3 are methyl groups, R4 is a
hydrogen atom, M is an aluminium atom, A is a kalium ion, and m is 1.

[0048]In chemical formula (2) representing the specific catechin gallate
metallic complexes (2), R1 is a hydrogen atom or hydroxyl group. If
R1 is a hydrogen atom, the specific catechin gallate metallic
complexes (2) represents the compound with the original ligand in the
epicatechin gallate derivative; If R1 is a hydroxyl group, the
specific catechin gallate metallic complexes (2) represents the compound
with the original ligand in the epigallocatechin gallate derivative.

[0049]In chemical formula (2), R2 and R3 independently represent
an alkyl group with 1-12 carbon atoms, an alkenyl group with 2-12 carbon
atoms, an alkoxy group with 1-12 carbon atoms, an aryl group with 6-12
carbon atoms, a nitryl group, an amidogen group, a halogen atom, or a
hydrogen atom; R2 and R3 can be the same or they can be
different groups.

[0059](2-1) In the compound of chemical formula (2), R1 is a hydroxyl
group, R2, R3, and R4 are hydrogen atoms, R5 and
R6 are water molecules, M is a cobalt atom, A is a sodium ion, and m
is 1.

[0060](2-2) In the compound of the chemical formula (2), R1, R2,
R3, and R4 are hydrogen atoms, R5 and R6 are water
molecules, M is a cobalt atom, A is a sodium ion, and m is 1.

[0061]The charge control agent constituted by the specific catechin
gallate metallic complexes (1) and the specific catechin gallate metallic
complexes (2) can be prepared by the following process.

[0062]For embodiment, the catechin gallate compounds shown in chemical
formula (3) (hereafter referred to as `raw catechin gallate compound`) is
dissolved in water or alcohols to prepare a raw catechin gallate compound
solution and the metal ion solution containing the metal ion that will be
used in the metal coordination reaction.

[0063]Then, the metal ion solution and the raw catechin gallate compound
solution is mixed with a molar ratio ranging from 1:3 to 1:2. During the
initial stage of the mixing process, the mixture should be weakly acidic,
i.e., the pH value should be slightly less than 7; then the pH value is
adjusted so that the solution is weakly basic (pH slightly greater than
7), and the solution is stirred for 6-48 hours at a temperature in the
range of 30° C.-90° C., so that the metal ion is
coordinated to form the metal complexes. The compound of chemical formula
(1) can be obtained:

[0064][In formula (3), R1 represents a hydroxyl group or an hydrogen
atom; R2 and R3 independently represent an alkyl group with
1-12 carbon atoms, an alkenyl group with 2-12 carbon atoms, an alkoxy
group with 1-12 carbon atoms, an aryl group with 6-12 carbon atoms, a
nitryl, an amidogen, a halogen atom, or a hydrogen atom; R4
represents a hydrogen atom, a potassium atom or a sodium atom.]

[0065]During the preparation of the complexes, the choices of raw catechin
gallate compounds and metal ion solution are based on the required type
of resultant catechin gallate metal complexes.

[0066]For embodiment, the metal ion solution can be, for example, a zinc
chloride solution, a chrome vitriol solution, or a zinc vitriol solution.

[0068]The mixed solution of raw catechin gallate compounds solution and
metal ion solution should be acidic (pH less than 7) at the initial
stage. The pH value at the initial stage should be above 3, and it is
preferred that the value be above 3.5. If the solution is more acidic
than the above value (i.e., the pH value is less than 3), the solubility
of the phenol hydroxyl group in the raw catechin gallic will be reduced,
and the reaction will be inhibited.

[0069]At this stage of adjusting the pH value, the solvent used to obtain
the metal ion solution can be, for example, hydrochloric acid or sulfuric
acid.

[0070]The next stage of the initial mixing is a stage in which raw
catechin gallate compound solution and metal ion solution are mixed and
the complexation reaction begins. It is necessary to ionize the phenol
hydroxyl group. So, the pH value of the solution is below 11, and the
preferred pH value is below 10. With the weak basic condition, the
ionization of the phenol hydroxyl group can occur, and therefore the
formation of the complexes can be improved.

[0071]During this complex formation stage, the pH value adjustment can be
achieved by adding, for example, sodium hydroxide, potassium hydroxide,
calcium hydroxide, or ammonia to the mixture.

[0072]In addition, in the mixed solution of raw catechin gallate compound
solution and metal ion solution, if the solvent is just alcohols, the pH
value of the mixed solution cannot be adjusted; if an alkali metal
alcoholate is used, e.g., sodium ethoxide or kalium ethoxide, the
reaction can be controlled by adjusting the quantity.

[0073]Then, the resultant of the above mentioned complexes preparation is
processed by after-treatments, such as washing and drying, and the charge
control agent of such metal complexes can be obtained by the complexes
preparation process.

[0075]The characteristics of the specific gallate metal complexes (1) and
specific gallate metal complexes (2) that are the resultant charge
control agent of the invention are: uniform crystal size, high charge
speed and high thermo stability, low moisture absorption, and good
compatibility with the resin. Thus, excellent charge control capability
can be obtained.

[0076]In addition, the metal ion coordination in the specific catechin
gallate complexes (1) and the specific catechin gallate complexes (2) is
very strong, which minimizes the disengagement of metal ions in the metal
complexes. Thus, in the cases in which such charge control agent are used
in the toner, the disadvantages caused by the free metal ion impurity
that is disengaged from the structure, such as metal bridging between
free metal ion and resin that undermines the toner characteristics and
results in high fluctuation of image quality in various environmental
humidity conditions, can be minimized.

[0077]The above mentioned charge control agent of the invention can be
used as an ingredient of toner as a developer for electrophotography, and
it has very good performance.

[0078]In the toner of the invention, which adopts the charge control agent
constituted by the above mentioned specific gallate metal complexes as a
necessary ingredient, the resin and colorant should be contained except
the charge control agent, and optional additives such as a release agent
that is used to improve fusing property, and other external additives.
These apply to both color and monochrome toners.

[0079]The components except the charge control agent of the toner in the
invention are not limited. All suitable publicly-known materials can be
adopted.

[0080]In embodiment, the resin can be a thermoplastic resin such as a
styrene acrylic resin, a polyester resin, and an epoxy resin. These
resins can be use separately or in combination.

[0081]The colorants can be a carbon black, a magnetic materials, a dye,
and a pigment. Carbon black used can be, for example, a channel black, a
furnace black, an acetylene black, a thermal black, and a gas black.

[0082]The magnetic materials can be a high-intensity magnetic materials
such as an iron, a nickel, a cobalt, and compounds of these, such as
alloy of these metals, ferrite, magnetite, and metal alloys that do not
contain high intensity magnetic metal but have high magnetism after heat
treatment, such as a Huesler alloy including manganese-copper-aluminum
and manganese-copper-tin alloys and a chromium dioxide.

[0095]The preferred average particle size range for these inorganic
particles from 5-300 nm. The particle size is determined under SEM x50000
by determining the average Feret diameter of 500 particles.

[0096]The amount of external additives used in the toner can be 0.1-5.0%
of total weight, preferably 0.5-4.0%. In addition, a combination of
above-mentioned materials can be used as external additives.

[0097]In addition, metal salt of higher fatty acid may also be used,
considering the transfer properties and cleaning properties, such as zinc
stearate, lithium stearate, or calcium stearate. The preferable amount of
such additives is 0.01-0.5% by weight.

[0098]If it is assumed that the total weight of the toner, except for the
charge control agent, is 110 units, then the proportion of the charge
control agent of the toner may be 0.1-3 units, preferably is 0.5-2.

[0099]If the toner contains an insufficient proportion of the charge
control agent, the toner may not have sufficient electrical
characteristics to function properly; in addition; if the toner contains
an excessive proportion of the charge control agent, the toner may not
have sufficient electric characteristics for the leakage of the charges
of the charge control agent, and the component of the figure-forming
device, such as the developing sleeve, will be polluted; especially if
the toner is used as a composing material of the bicomponent developer,
the polluted carrier will cause the toner not to have appropriate
electrical characteristics.

[0100]The preparation methods of toner of the present invention quite
flexible, and generally adopted methods such as the
melting-kneading-pulverization method, suspension polymerization method,
emulsion aggregation method, mini-emulsion aggregation method, polyester
expansion method, and other publicly known methods can be used.

[0101]If the melting-kneading-pulverization method is selected as the
method for preparing the charge control agent, the attraction between the
charge control agent and the metal ion is very strong, so there will not
be disengagement of metal ions. Thus, the disadvantages caused by metal
bridging between free metal ion and resin that undermines the toner
characteristics will not present, and the fixation characteristics will
not be diminished. In addition, the dispersion characteristics of the
invention is excellent; it is easy to disperse in resin.

[0102]In addition, if the polymerization reaction method is used as the
method for preparing the charge control agent, the attraction between the
charge control agent and the metal ion is very strong, as described
above, and this prevents the charge control agent from being dissolving
or otherwise decomposing during dispersion in the aqueous medium.
Further, for the existence of metal coordination binding and ion binding,
the dispersability of the charge control agent in aqueous medium is good,
and it is easy to form micro particles of the charge control agent. In
addition, its dispersability in monomer and solvent is good.

[0103]The following are the records of toner preparation methods.

[0104]1) Melting-Kneading-Pulverization Method

[0105]In the pulverization method, first, the powder of resin, colorant
and the charge control agent of the present invention and optional
release agent are dry-mixed (premix). Then, equipment, such as a twin
roller extruder, is used to melt and knead the components, and the
resulting mixture is cooled, pulverized, and classified to obtain the
resultant toner. Pulverization can be either mechanical grinding or jet
milling.

[0106]2) Emulsion Aggregation and Mini-Emulsion Aggregation Method

[0107]Emulsion aggregation method refers to a preparation method in which
resin particles, colorant particles, and charge control agent particles
of the present invention are aggregated and fused to form toner
particles. In this method, an optional release agent may also be used. In
this method, the preferred average size of resin particles, colorant
particles, and charge control agent particles of the present invention is
between 50-200 nm. In a preferred method, the monomer particles are
directly aggregated in an aqueous medium by emulsion aggregation reaction
or mini-emulsion aggregation reaction to form toner particles. In such
method, uniform particle sizes can be obtained. The colorant particles
can be achieved by using a mechanical homogenizer with the presence of
surfactant in water. The homogenizer used can be CLEARMIX or bead miller.
The charge control agent of the present invention can be dispersed using
the same mechanical homogenizer as was used for the colorant.

[0108]3) Suspension Polymerization Method

[0109]First, the monomer, colorant, the charge control agent of the
present invention, a polymerization initiator and the optional release
agent are mixed. Second, a mixer is used to disperse the colorant, the
charge control agent of the present invention, and the optional release
agent in a monomer. Third, the mixture is dispersed in an aqueous medium
with disperse stabilizer and oil drops are formed. Fourth, the
polymerization reaction of the monomer is initiated. Fifth, the dispersed
stabilizer in the polymerized monomer is removed, and the resultant
substance is filtered and dried to produce the toner. In this method, the
disperse stabilizer is easy to remove; the preferred examples include the
use of an almost insoluble inorganic colloid, such as calcium phosphate.

[0110]4) Polyester (Elongation) Polymerization Method

[0111]The denatured polyisocyanate, multivalent amine used as molecular
elongation agent, colorant, the charge control agent of the present
invention, and an optional release agent are added to a solvent and
mixed. The liquid is dispersed in an aqueous medium to form oil drops,
and the mixture is heated to expansion the molecules. Then, the solvent
is removed, the shape of the particle is controlled, and the resultant
substance is filtered and dried to produce toner.

[0112]The above-mentioned toner of the present invention can be used as
magnetic or non-magnetic mono-component developer, or it can be mixed
with carrier to use as a dual-component developer.

[0113]In the cases in which such toner is used as magnetic monochrome
developer, the suitable black colorants are magnetite, preferably with an
average particle size in the range of 80-200 nm. The crystal shape of
magnetite can be cubic, spherical, and octahedral. If reddish toner is
desired, spherical shape magnetite is preferred. If the bluish toner is
desired, cubic shape magnetite is preferred. The amount of coloring agent
used as magnetic mono-component developer in the toner varies with the
various developing methods. In the non-contact developing method, the
preferred amount of coloring agent is 35-45% of the total weight of the
toner. If the amount used is too small, dusting may occur. On the other
hand, over usage of coloring agent may result in inferior developing
properties.

[0114]On occasions in which dual-component developer is used, the carrier
in such dual-component toner can be selected from iron, ferrite,
magnetite, or an alloy of these metals with publicly-known metals, such
as aluminum or lead. Ferrite is a preferred choice. It is preferred that
the alloy not contain copper and zinc, but it may contain light alkali
metals or light alkaline earth metals alloyed with ferrite. In addition,
if these metals are used as the core of carrier, it is preferred to coat
the core with silica resin, styrene acrylic resin, acrylic resin, or
resin containing florin. The preferred average size of the carrier
particles is 30-100 μm.

[0115]The above-mentioned toner of the present invention contains charge
control agent, which provides excellent charge control properties. Thus,
in different temperature and humidity conditions, whether temperature and
humidity values are high or low, high-quality image can be ensured. In
addition, due to the excellent charge ability, there is no possibility of
dusting and fogging caused by unevenly-charged toner particles. Thus,
high-quality image can be obtained.

[0116]In such toner, the ion coupling strength in the catechin gallate
metal complexes, which is used as the charge control agent, is very
strong and prevents the detachment of the metal ions that form the metal
complexes. So, the problems caused by the free metal ion as an impurity,
such as the bridging between metal ions and the resin that destroys the
desired toner properties or large variations of image quality under
different environments, can be minimized. Thus, excellent image quality
can provided by the toner of the present invention, even in
low-temperature fusing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0117]Tables 1-8 show physical characteristics of toners in accordance
with various embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0118]The following are embodiments of the invention, but they should not
form a limit to the invention.

Embodiment 1 for Preparing Charge Control Agent

[0119]The 187 g of catechin gallate in the above formula (3), in which
R1 is a hydroxyl group, and R2-R4 are hydrogen atoms
(referred to as [raw material compound (1) hereafter]), are placed in
carbinol to obtain a solution with a concentration of 2 mol/L. Dissolve
23 g of zinc chloride in water to get a 3 mol/L solution, and adjust the
pH of the solution to 10.0 by adding an ethanol solution that contains 4
mol/L of ethanol sodium. The raw material (1) solution is slowly added
into the former solution, and the solution is maintained at 90° C.
for 24 hours with mixing sufficiently, and the resultant crystalline
product is filtered. Then, the resultant material is washed, dried, and
crushed to obtain the powder metal complexes (hereafter referred to as
[charge control agent (1)])173 g.

[0120]The resultant charge control agent (1) in Chemical Formula (1) is a
catechin gallate metal complexes in which R1 is a hydroxyl group,
R2-R4 are hydrogen atoms, M is a zinc atom, A is a sodium atom,
and m is 1. (Example compound (1-1))

Embodiment 2 for Preparing Charge Control Agent

[0121]The 91 g catechin gallate of above formula (3), in which
R1-R4 are hydrogen atoms (refer to as [raw material compound
(2) hereafter]), is put into ethanol containing 1% ethanol sodium to
obtain the 150 ml material (2) solution. Then, 23 g of zinc chloride are
dissolved in ethanol to get a 5 mol/L solution, and the raw material (2)
solution is slowly added to the former solution, and the solution is
maintained at 50° C. for 30 hours with mixing sufficiently, and
the resultant crystalline product is filtered. Then, the resultant
material is washed, dried, and crushed to obtain the powder metal
complexes (hereafter referred to as [charge control agent (2)])170 g.

[0122]The resultant charge control agent (2) in Chemical Formula (1) is a
catechin gallate metal complexes in which R1-R4 are hydrogen
atoms, M is a zinc atom, A is a sodium atom, and m is 1. (Example
compound(1-2))

Embodiment 3 for Preparing Charge Control Agent

[0123]The 200 g material compound (1) is put into 1.5 L of water to get
raw material compound (1) solution. Then, 37 g of chrome vitriol is
dissolved in 200 ml of water, and a 6 mol/L solution of hartshorn is
slowly added to adjust the pH to 8.0, the above raw material compound (1)
solution is added, the solution is maintained at 80° C. for 24
hours with mixing sufficiently, and the resultant crystalline substance
is filtered. Then, the resultant material is washed, dried, and crushed
to obtain the powder metal complexes (hereafter referred to as [charge
control agent (3)])173 g.

[0124]The resultant charge control agent (3) in Chemical Formula (1) is a
catechin gallate metal complexes in which R1 is an hydroxyl group,
R2-R4 are hydrogen atoms, M is a chromium atom, A is
NH4.sup.+, and m is 1. (Example compound(1-3))

Embodiment 4 for Preparing Charge Control Agent

[0125]The 250 g of raw material compound (1) are put into ethanol to get 1
mol/L raw material compound (1) solution. Then, 30 g of iron vitriol are
dissolved in 40 ml of water, and 5 mol/L sodium hydroxide solution is
slowly added to adjust the pH to 8.5, the above raw material compound (1)
solution is added to adjust the pH of the mixed solution to 8.5, the
solution is maintained at 70° C. for 15 hours with mixing
sufficiently, and the resultant crystalline substance is filtered. Then,
the resultant material is washed, dried, and crushed to obtain the powder
metal complexes (hereafter referred to as [charge control agent (4)])228
g.

[0126]The resultant charge control agent (4) in Chemical Formula (1) is a
catechin gallate metal complexes in which R1 is an hydroxyl group,
R2-R4 are hydrogen atoms, M is a iron atom, A is a sodium atom,
and m is 1. (Example compound(1-4))

Embodiment 5 for Preparing Charge Control Agent

[0127]The 200 g of raw material compound (2) is put into 1.5 L of water to
get material compound (2) solution. Then, 37 g of chrome vitriol is
dissolved in 200 ml of water, the 6 mol/L hartshorn is slowly added to
adjust the pH to 8.5, the above raw material compound (2) is added, the
solution is maintained at 80° C. for 24 hours with mixing
sufficiently, and the resultant crystalline substance is filtered. Then,
the resultant material is washed, dried, and crushed to obtain the powder
metal complexes (hereafter referred to as [charge control agent (5)])170
g.

[0128]The resultant charge control agent (5) in Chemical Formula (1) is a
catechin gallate metal complexes in which R1-R4 are hydrogen
atoms, M is a chromium atom, A is an ammonium ion, and m is 1. (Example
compound(1-5))

Embodiment 6 for Preparing Charge Control Agent

[0129]The 200 g of material compound (1) is put into 1.5 L of water to get
raw material compound (1) solution. The, 40 g of cobalt chloride is
dissolved in 200 ml of water, caustic soda is slowly added to adjust the
pH to 9.5, the above raw material compound (1) is added, the solution is
maintained at 80° C. for 24 hours with mixing sufficiently, and
the resultant crystalline substance is filtered. Then, the resultant
material is washed, dried, and crushed to obtain the powder metal
complexes (hereafter referred to as [charge control agent (6)])170 g.

[0130]The resultant charge control agent (6) in Chemical Formula (2) is a
catechin gallate metal complexes in which R1 is an hydroxyl group,
R2-R4 are hydrogen atoms, R5 and R6 are water
molecule, M is a cobalt atom, A is a sodium atom, and m is 1. (Example
compound(2-1))

Embodiment 7 for Preparing Charge Control Agent

[0131]The 200 g raw material compound (2) is put into 1.5 L of water to
get raw material compound (2) solution. Then, 40 g of cobalt chloride is
dissolved in 200 ml of water, caustic soda is slowly added to adjust the
pH to 9.5, the above raw material compound (2) is added, the solution is
maintained at 80° C. for 24 hours with mixing sufficiently, and
the resultant crystalline substance is filtered. Then, the resultant
material is washed, dried, and crushed to obtain the powder metal
complexes (hereafter referred to as [charge control agent (7)])170 g.

[0132]The resultant charge control agent (7) in Chemical Formula (2) is a
catechin gallate metal complexes in which R1-R4 are hydrogen
atoms, R and R are water molecule, M is a cobalt atom, A is a sodium
atom, and m is 1. (Example compound(2-2))

Embodiment 8 for Preparing Charge Control Agent

[0133]The 191 g compound of formula (3) (referred to as [material compound
(3) hereafter])in which R1 is a hydroxyl group, R2 and R3
are methyl ions, and R4 is a hydrogen atom, are put into carbinol to
obtain a 2 mol/L raw material (3) solution. Then, 23 g of zinc chloride
are dissolved in water to get a 3 mol/L solution, and the pH value is
adjusted to 10.0 by adding ethanol solution that contains 4 mol/L of
ethanol sodium. The raw material (3) solution is slowly added to the
former solution, and the resulting solution is maintained at 90°
C. for 24 hours with mixing sufficiently, and the resultant crystalline
substance is filtered. Then, the resultant material is washed, dried, and
crushed to obtain the powder metal complexes (hereafter referred to as
[charge control agent (8)])173 g.

[0134]The resultant charge control agent (8) in chemical formula (1) is a
catechin gallate metal complexes in which R1 is a hydroxyl group,
R2 and R3 are methyl groups, R4 is an hydrogen atom, M is
a zinc atom, A is a sodium atom, and m is 1. (Example compound(1-6))

Embodiment 9 for Preparing Charge Control Agent

[0135]The 200 g compound of formula (3), in which R1 is a hydroxyl
group, R2 and R3 are chlorine atoms, and R4 is an hydrogen
atom, (refer to as [raw material compound (4) hereafter]), are put into
carbinol to obtain a 2 mol/L raw material (4) solution. Then, 23 g of
zinc chloride are dissolved in water to get a 3 mol/L solution, and the
pH value is adjusted to 10.0 by adding ethanol solution containing 4
mol/L of ethanol sodium. The raw material (4) solution is slowly added
into the former solution, and the resulting solution is maintained at 90
for 24 hours with mixing sufficiently, and the resultant crystalline
substance is filtered. Then, the resultant material is washed, dried, and
crushed to obtain the powder metal complexes (hereafter referred to as
[charge control agent (9)])173 g.

[0136]The resultant charge control agent (9) in chemical formula (1) is a
catechin gallate metal complexes in which R1 is a hydroxyl group,
R2 and R3 are chlorine atoms, R4 is an hydrogen atom, M is
a zinc atom, A is a sodium atom, and m is 1. (Example compound(1-13))

[0137]The charge control agent obtained from the preparation embodiment 1
to preparation embodiment 9 are used to make toner according to the
following methods, and the obtained toner is used to produce developer.

Embodiment 1 for Preparing Toner with Pulverization Method

[0138]One part of charge control agent (1), 100 parts of styrene-acrylic
resin (styrene:butyl acrylate:methyl methacrylate=70:20:5 (by weight),
softening point is 128° C.), 8 parts of carbon black `MOGUL L`
(manufactured by Cabot Co.) and 6 parts of low-molecular weight
polypropylene `660P` (manufactured by Sanyo Chemical) are mixed in a
Henschel mixer. The resultant mixture is melted and kneaded with a
twin-screw extruder, cooled, pulverized with a jet mill, and classified
with a cyclone classifier to obtain colored particles with an average
diameter of approximately 8.5 μm.

[0139]Then 0.8 part of 67% hydrophobic silica dioxide with an average
diameter of 12 nm is added into every 100 parts of the colored particles.
The resultant mixture is mixed with a Henschel mixer to obtain the toner.

[0141]In the embodiments 1 for preparing toner with pulverization method,
the charge control agent listed in Table 1 are used to replace the charge
control agent (1), and other conditions are the same as the conditions
used for the embodiments 1 for preparation of toner with pulverization
method, to obtain toner.

[0142]Hereafter, the toners using the charge control agent (1) to charge
control agent (9) listed in the Table 1 are named as toner (1)-toner (9).
In addition, chromium salicylate complexes [E-81] (manufactured by Orient
Chemical Co.), calixarene derivative [E-88] (manufactured by Orient
Chemical Co.), and chromium azo complexes [S-34] (manufactured by Orient
Chemical Co.) as comparative charge control agent, are used to obtain
comparative toner, as shown in Table 1, which are named as comparative
toner (1)-comparative toner (3).

[0144]One part of charge control agent, 75 parts of styrene monomer, 25
parts of butylacrylate, 5 parts of MOGUL L, 3 parts of copper
phthalocyanine pigment (C.I. P.B. 15:3) and 2 parts of Azobis
(isovaleronitrile) are mixed. The resultant mixture is dispersed in a
sand mill at 10,000 rpm for 30 minutes to obtain a mixture of
polymerizable monomer.

[0145]Then, 600 parts of ion exchanged water and 500 parts of a 0.1 mol/L
solution of Na3PO4 in water are placed in a 4-neck, 2 L flask
equipped with a high-speed mixing device (TK homogenizer manufactured by
PRIMIX Corporation) and a baffle plate. The solution is mixed at 12,000
rpm at 65° C. Then, 70 parts of a 1.0 mol/L solution of CaCl2
in water are slowly added to prepare an aqueous dispersion medium
containing weenies dispersion stabilizer Ca3(PO4)2 which
is hardly soluble in water.

[0146]Then, the polymerizable monomer mixture is added to the aqueous
dispersion medium, stirring is continued at 12,000 rpm for 15 minutes in
a nitrogen gas environment at 65° C. to form particles of the
polymerizable monomer composite. The stirring blade is exchanged for a
spiral stirring blade, and the shape of the particles is controlled by
the stirring speed and the angle of the baffle plate. The temperature is
maintained for 10 hours to complete the polymerization. After the
completion of the polymerization, the suspension liquid is cooled, and
dilute hydrochloric acid is added to remove dispersion stabilizer. The
resultant mixture is washed with water for times, and dried to obtain
colored particles with a volume average diameter of 8.2 μm.

[0147]Then 0.8 part of 67% hydrophobic silica dioxide with a number
average diameter of 12 nm is added into 100 parts of the colored
particles. The resultant mixture is mixed with a Henschel mixer to obtain
the toner.

[0148]In embodiment 1 for preparing toner with suspension polymerization
method, the charge control agent listed in Table 3 are used to replace
the charge control agent (1). The other conditions are the same as the
conditions used in the embodiment 1 for preparing toner with suspension
polymerization method, to obtain toner.

[0149]Hereafter, the toner with suspension polymerization method using the
charge control agent (1) to charge control agent (9) listed in the Table
3 are named as toner (10)-toner (18). In addition, chromium salicylate
complexes [E-81] (manufactured by Orient Chemical Co.), calixarene
derivative [E-88] (manufactured by Orient Chemical Co.), and chromium azo
complexes [S-34] (manufactured by Orient Chemical Co.) as comparative
charge control agent are used to obtain comparative suspension
polymerized toner, as shown in Table 3, which are named comparative toner
(4)-comparative toner (6).

Embodiment 1 for Preparing Toner with Emulsion Aggregation Method

[0150]1) Preparing the Dispersion Liquid of Resin Particles

[0151]A solution of 16 parts of sodium dodecylsulfate is added into 1500
parts of ion exchanged water in a reactor with a stirring device,
temperature sensor, cooling tube and nitrogen injector. The solution is
stirred under nitrogen gas current at 230 rpm and heated to 80 Then, a
solution of 5 parts of potassium persulfate in 100 parts of ion exchanged
water is added to the system, and the system is heated again to
80° C. In one hour, a polymerizable monomer liquid that contains
350 parts of styrene, 125 parts of n-butylacrylate, 25 parts of
methacrylic acid, and 4 parts of n-dodecyl mercaptan is dropped into the
reactor. The resultant solution is heated to 80° C. for 2 hours
and mixed to allow polymerization to prepare resin particle dispersion
liquid (1).

[0152]The electrophoresis light scattering photometer (ELS-800)
(Manufactured by Osuka Electronics Co., Ltd.) is used to determine the
particle size in the resin particle dispersion liquid (1), the volume
average diameter of which is 110 nm.

[0155]The electrophoresis light scattering photometer (ELS-800)
(Manufactured by Osuka Electronics Co., Ltd.) is used to determine the
particle size in the colorant dispersion liquid (1), the volume average
diameter of which is 120 nm.

[0156]3) Preparing Charge Control Agent Dispersion Liquid

[0157]Five parts of sodium dodecylsulfate are dissolved in 200 parts of
ion exchanged water. Five parts of charge control agent (1) are slowly
added into the solution. The resultant product is dispersed with a sand
mill to prepare a charge control agent dispersion liquid (1).

[0158]The electrophoresis light scattering photometer (ELS-800)
(Manufactured by Osuka Electronics Co., Ltd.) is used to determine the
particle size in the colorant dispersion liquid (1), the volume average
diameter of which is 110 nm.

[0159]4) Preparing Release Agent Dispersion Liquid

[0160]The solution of 6 parts of sodium sulfate in 200 parts of ion
exchanged water is heated to 90 while stirring, 40 parts of melted
carnauba wax at 90 are slowly added, sonication is used to disperse the
particles, and a wax dispersion liquid (1) is formed.

[0161]The electrophoresis light scattering photometer (ELS-800)
(Manufactured by Osuka Electronics Co., Ltd.) is used to determine the
particle size in the colorant dispersion liquid (1), the volume average
diameter of which is 130 nm.

[0162]5) Aggregating (Fusing) with Resin Particle

[0163]The above mentioned resin particle dispersion liquid (1), colorant
dispersion liquid (1), charge control agent dispersion liquid (1),
release agent (1), disperse agent (1) and 1400 parts of ion exchanged
water are placed in a reactor that has a stirring device, temperature
sensor, cooling tube, and nitrogen injector, and a solution of 10 parts
of polyoxyethylene-2-sodium dodecylsulfate ether in 500 parts of ion
exchanged water is added to this mixture. The temperature of the system
is adjusted to 30, and the pH value is adjusted to 10 with a 5 N solution
of sodium hydroxide in water.

[0164]Then 100 parts of magnesium chloride is dissolved in 100 parts of
ion exchanged water and added to the mixture at 30 over a 10-minute
period with continuous stirring. After the addition is completed,
stirring is continued for an additional three minutes, and the system is
gradually heated to 90 over a 60-minute time period. The temperature is
maintained at 90 to let the particles aggregate. The `Coulter Multilizer
III` is used to determine the size of the aggregated particles. When the
desired particle size is obtained, a solution of 300 parts of sodium
chloride in 1000 parts of ion exchanged water is added to stop particle
growth. The mixture is heated to 98 to let the particles fuse until the
average roundness of the particles is 0.965 as determined by testing with
`FPIA-2100.` The liquid is cooled to 30, the pH value is adjusted to 4.0
with hydrochloric acid, and stirring is stopped to obtain toner.

[0165]In the embodiment 1 for preparing toner with emulsion aggregation
method, the charge control agent listed in Table 5 are used to replace
the charge control agent (1), and other conditions are the same as the
conditions used in the embodiment 1 for preparing toner with emulsion
aggregation method, to obtain toner.

[0166]Hereafter, the toner with emulsion aggregation method using the
charge control agent (1) to charge control agent (9) listed in the Table
1 are named as toner (19)-toner (27). In addition, chromium salicylate
complexes [E-81] (manufactured by Orient Chemical Co.), calixarene
derivative [E-88] (manufactured by Orient Chemical Co.), and chromium azo
complexes [S-34] (manufactured by Orient Chemical Co.) are used as
comparative charge control agent to obtain comparative emulsion
aggregated toner, as shown in Table 5, which are named comparative toner
(7)-comparative toner (9).

[0169]Place 724 parts of bisphAlkenyl A ethylene oxide and 2 mol additive,
200 parts of isophthalic acid, 70 parts of fumaric acid, and 2 parts of
dibutylin oxide in a reactor that has a mixer and a nitrogen injection
device. The resulting mixture is reacts at a temperature of 230 and
atmospheric pressure for 8 hours and reacts at a pressure of 12 mm Hg for
5 hours. The system is cooled to 160, 32 parts of phthalic anhydride are
added, and the solution is reacted for 2 hours to obtain unformed
polyester [a1].

[0170]The unformed polyester [a1] has a glass transition point of 59 and a
softening point of 121, a number average molecular weight (Mn) of 6,000,
and a weight average molecular weight (Mw) of 28,000.

[0171]Then 1,000 parts of the unformed polyester [a1] are added for every
2,000 parts of ethyl acetate, and 120 parts of isophorone diisocyanate
are added. The resultant solution is reacted at 80 for 2 hours to obtain
denatured polyisocyanate [1].

[0172]Place 450 parts of ethyl acetate, 300 parts of denatured
polyisocyanate [1], 14 parts of isophoronediamine, 4 parts of copper
phthalocyanine blue, 4 parts of carbon black, 15 parts of camauba wax,
and 3 parts of charge control agent (1) in a reactor that has a hydraulic
seal and a stirrer and react the mixed solution at 20° C. for 2
hours to obtain toner composite [1].

[0173]At the same time, 600 parts of ion exchanged water, 60 parts of
methyl ethyl ketone, 60 parts of tricalcium phosphate, and 0.3 part of
sodium dodecyl benzene sulfonate are put into another reactor. The mixed
solution is stirred with a TK homogenizer (manufactured by PRIMIX
Corporation) at 15,000 rpm at a temperature of 30 for 3 minutes. Then,
the above mentioned toner composite [1] is added to the mixture to
disperse in a aqueous medium, heated to 80, and treated with urea for 10
hours to obtain particles with a volume average diameter of 5.5 μm.

[0174]The urea-treated toner composite [1] is moved to another mixer, 0.3
part of sodium dodecylsulfate is added at 30, heated to 50, and react for
3 hours to let the particle surface coalescent with the dodecyl group.
Then, the resultant solution is rapidly heated to 80 to remove ethyl
acetate. After the ethyl acetate has been completely removed, the system
is cooled to room temperature; 150 parts of 35% hydrochloric acid are
added to remove the tricalcium phosphate on the surface of the toner
particles.

[0175]The liquid and the solid are separated, and the dehydrated toner
press cake is dispersed in ion exchange water. This separation process is
repeated 3 times, and the product is washed and then dried at 40 for 24
hours to obtain toner particle [Bk1].

[0176]In the embodiment 1 for preparing toner with Polyester (Elongation)
Polymerization method, the charge control agent listed in Table 7 are
used to replace the charge control agent (1), and other conditions are
the same as the conditions used in the embodiment 1 for preparing toner
with Polyester (Elongation) Polymerization method.

[0177]Hereafter, the polyester expansion polymerized toners using the
charge control agent (1) to charge control agent (9) listed in the Table
7 are named as toner (28)-toner (36). In addition, the comparative
polyester expansion polymerized toners of chromium salicylate complexes
[E-81] (manufactured by Orient Chemical Co.), calixarene derivative
[E-88] (manufactured by Orient Chemical Co.), and chromium azo complexes
[S-34] (manufactured by Orient Chemical Co.), which are used as the
comparative charge control agent, are shown in Table 7, which are named
as comparative toner (10)-comparative toner (12).

Embodiments 1-36 and Comparative Embodiments 1-12

[0178]The toners and the carrier comprised of light metal ferrite coated
with silicone with volume average size of 65 μm are mixed to obtain
duel-component developers containing 8% toner.

[0179]Then the dual-component developers using toner (1)-toner (36) are
named as developer (1)-developer (36). And the dual-component developers
using comparative toner (1)-comparative toner (12) are named as
comparative developer (1)-comparative developer (12).

[0180]The following methods are used to evaluate the developer
(1)-developer (36) and the comparative developer (1)-comparative
developer (12). The results are shown in the following Tables 1-8.

[0181](1) Charge Characteristics

[0182]One gram of each kind of toners, which are used to produce developer
(1)-developer (36) and comparative developer (1)-comparative developer
(12), are separately put into a 20-ml, glass test tube with 10 g of
carrier. At conditions of 20 and 50% RH, the resultant substance is
stirred with a YAYOI shaker for 1 minute, 2 minutes, 5 minutes, 10
minutes, 20 minutes, and 60 minutes. Under room temperature and normal
humidity, the resultant substance is tested with a TB-200 charge-amount
testing apparatus (manufactured by Toshiba, Co.) to determine the charge
amounts.

[0183](2) Charge Stability

[0184]One gram of each kind of toners, which are used to produce developer
(1)-developer (36) and comparative developer (1)-comparative developer
(12) are separately put into a 20-ml, glass test tube with 10 g of
carrier. Under room temperature and normal humidity, the resultant
substance is tested with a TB-200 charge amount-testing apparatus
(manufactured by Toshiba, Co.) to determine the charge amounts (shown in
Table 1 as initial charge amount). Then, the resultant substance is
stored at 35 and 85% RH for 24 hours, the charge amount is tested again
(shown as charge amount after storage in tables).

[0185](3) Image Quality

[0186]The respective developers, developer (1)-developer (36) and
comparative developer (1)-comparative developer (12), are used by the
contacting image method to produce image of A4 size and pixel rate of 5%
in a photocopier (Ricoh Imagio Neo 1050Pro) that has a maximum speed of
105 pages per minute at 20 and 50% RH environment, as well as at 35 and
85% RH. The image copying mode is that image formation pauses for 1
minute after every 50 pages using A4 photocopy paper for a total 500,000
pages. The image density of the black image of the initial image (shown
as `initial`), the 500,000th image (shown as 500,000th), and
the fog density of the blank space in these pages are tested with
`RD-918` of Macbeth Company. The tests are conducted regarding the
reflecting rate of the copying paper as `0` to determine the relative
reflect rate of the image.

[0187]In addition, the character resolution of the initial image and the
500,000th image is observed with a 10× magnifier. While
observed visually, the toner charge amount of the initial image and the
500,000th image are tested.

[0188]While particular embodiments of the invention have been shown and
described, to those skilled in the art it will be obvious that changes
and modifications may be made without departing from the invention in its
broader aspects, and, therefore, the aim in the appended claims is to
cover all such changes and modifications as fall within the true spirit
and scope of the invention.